I have a 400ex with various aftermarket parts and I have a FMF Titanium 4 exhaust on my 400 and wondering if this slip on makes it too loud? not enough power, any review or have you put this slip on, on your quad?

 

This isn't really helping with the Fmf pipe(sorry), but i have a warrior 350 and i put a Hmf competition pipe on it and i am very happy with it, it was well worth the money, the nice thing about it is that it has three inserts, Stage 1, Stage2, Stage3, Stage 3 being the loudest. On my bike stage three is really loud. This is a list of the decibles for the stages

Stage 1- low to mid 90's
Stage 2- mid to high 90's
Stage 3- high 90's to low 100's

That is the scale on there website but it varies for every bike so like for my bike it might be loud but for yours it might be louder it just depends on the bike. so if you plan on looking at one of those pipe i would do some research on how loud it is for your bike.